GB/T 13747.3-2020Methods for chemical analysis of zirconium and zirconium alloys－Part 3: Determination of nickel content－Dimethyglyoxime spectrophotometry and inductively coupled plasma atomic emission spectrometry (English PDF)

2.1 Principle

The sample is dissolved in hydrofluoric acid, the excess hydrofluoric acid is complexed with a saturated solution of boric acid, the main zirconium is complexed with citric acid, and iodine is used as the oxidant.

In the solution, nickel and dimethylglyoxime form a red complex, and its absorbance is measured at a wavelength of 540nm with a spectrophotometer.

2.2 Reagents

Unless otherwise stated, only reagents and laboratory secondary water confirmed to be analytically pure are used in the analysis.

2.2.1 Nitric acid (1 1).

2.2.2 Hydrofluoric acid (rho=1.13g/mL).

2.2.3 Saturated solution of boric acid.

2.2.4 Citric acid solution (200g/L).

2.2.5 Ammonia (1 1).

2.2.6 Iodine solution. Weigh 1.3g of iodine and 5g of potassium iodide in a 500mL beaker, dissolve and dilute to 500mL with water, and store in brown In the bottle.

2.2.7 Diacetyl oxime-ethanol solution (2g/L). Weigh 1.0 g of diacetyl oxime and dissolve it in 500 mL of ethanol.

2.2.8 Nickel standard storage solution. Weigh 1.0000g metallic nickel (wNi>=99.99%) into a 250mL beaker, add 10mL nitric acid (2.2.1), heat to dissolve, add 10mL sulfuric acid (1 1), heat until sulfuric acid fumes, and then transfer to a 1000mL volumetric flask, dilute with water Release to the mark and mix well. This solution 1mL contains 1mg nickel.

2.2.9 Nickel standard solution. Pipette 50.00mL nickel standard stock solution (2.2.8) into a 1000mL volumetric flask, dilute to the mark with water, and mix uniform. 1mL of this solution contains 50µg of nickel.

2.3 Apparatus

Spectrophotometer.

2.4 Sample

Process the sample into chips with a length not greater than 5mm.

2.5 Test procedure

2.5.1 Sample

Weigh the sample (2.4) according to Table 1, accurate to 0.0001g.

2.5.2 Parallel test

Do two tests in parallel and take the average value.

2.5.3 Blank test

Do a blank test with the sample.

2.5.4 Determination

2.5.4.1 Place the sample (2.5.1) in a 100mL polytetrafluoroethylene beaker, blow in a small amount of water, and add hydrofluoric acid (2.2.2) dropwise according to Table 1.

After the sample is dissolved, add 0.5 mL of nitric acid (2.2.1) until the solution is clear, add 25 mL of boric acid saturated solution (2.2.3), and transfer to a 100 mL volume. In a measuring flask, dilute to the mark with water and mix well.

2.5.4.2 Pipette 20.00mL solution (2.5.4.1) into a 50mL volumetric flask.

2.5.4.3 Add 4 mL of citric acid solution (2.2.4) and 2.5 mL of iodine solution (2.2.6), mix well, let stand for 3 minutes, and add ammonia water (2.2.5) dropwise to dissolve The color of iodine in the solution disappeared and an excess of 5 mL was made. Cool to room temperature.

2.5.4.4 Add 2mL of diacetyl oxime-ethanol solution (2.2.7), dilute to the mark with water, mix well, and place for 15min.

2.5.4.5 Pipette part of the solution into a 3cm cuvette, use the blank solution with the sample as a reference, and place it at the wavelength of 540nm on the spectrophotometer Measure its absorbance.

2.5.4.6 Check the corresponding amount of nickel from the working curve, subtract the absorbance of the blank test solution.

2.5.5 Drawing of working curve

2.5.5.1 Pipette 0mL, 0.10mL, 0.50mL, 1.00mL, 1.50mL, 2.00mL nickel standard solution (2.2.9), put them in a group In a 50mL volumetric flask, dilute with water to about 20mL, and proceed as follows in 2.5.4.3 and 2.5.4.4.

2.5.5.2 Pipette part of the solution into a 3 cm cuvette, use the reagent blank solution as a reference, and measure it at a wavelength of 540 nm with a spectrophotometer.

Absorbance, using nickel content as the abscissa and absorbance as the ordinate to draw the working curve.

2.6 Test data processing

The nickel content is calculated as the mass fraction of nickel wNi, calculated according to formula (1).

Where.

m1---Check the amount of nickel from the working curve, in micrograms (µg);

V0---Total volume of test solution, in milliliters (mL);

m0---The mass of the sample, in grams (g);

V1--- Divide the volume of the test solution in milliliters (mL).

When the calculation result is less than 0.010%, one significant digit is reserved; when the calculation result is >=0.010%, two significant digits are reserved.

2.7 Precision

2.7.1 Repeatability

The measured values of two independent test results obtained under repeatability conditions are within the range of the average value given in Table 2.

The absolute difference does not exceed the repeatability limit (r), and the case of exceeding the repeatability limit (r) does not exceed 5%. Repeatability limit (r) adopts the line according to the data in Table 2 Obtained by sexual interpolation or extension method.

2.7.2 Reproducibility

The measured values of two independent test results obtained under reproducibility conditions are within the range of the average value given in Table 3.

The absolute difference does not exceed the reproducibility limit (R), and does not exceed 5% in the case of exceeding the reproducibility limit (R). Reproducibility limit (R) is adopted according to the data in Table 3 Obtained by linear interpolation or extension method.

3.1 Principle

Dissolve the sample with hydrochloric acid and hydrofluoric acid, add nitric acid dropwise to oxidize. Determined by inductively coupled plasma atomic emission spectrometry, press work The curve method calculates the mass concentration of nickel and expresses the measurement result in mass fraction.

3.2 Reagents

Unless otherwise stated, only reagents and laboratory secondary water confirmed to be analytically pure are used in the analysis.

3.2.1 Nitric acid (rho=1.42g/mL).

3.2.2 Hydrochloric acid (1 1).

3.2.3 Hydrofluoric acid (11).

3.2.4 Metal zirconium (wZr>=99.95%, wNi< 0.0005%).

3.2.5 Nickel standard stock solution. Weigh 1.0000g metallic nickel (wNi>=99.99%) into a 250mL beaker, add 25mL nitric acid (3.2.1), cover with a watch glass, dissolve at low temperature, cool, transfer to a 1000mL volumetric flask, dilute to the mark with water, and mix. This solution 1mL contains 1mg nickel.

3.2.6 Nickel standard solution. pipette 10.00mL nickel standard stock solution (3.2.5) into a 100mL volumetric flask, add 1mL nitric acid (3.2.1), dilute to the mark with water, and mix well. This solution 1mL contains 100µg nickel.

3.2.7 Argon gas (volume fraction >=99.99%).

3.3 Apparatus

Inductively coupled plasma atomic emission spectrometer, with hydrofluoric acid resistant sampling system.

3.4 Sample

Process the sample into chips with a length not greater than 5mm.

3.5 Test procedure

3.5.1 Sample

Weigh 0.50g sample (3.4), accurate to 0.0001g.

3.5.2 Parallel test

Do two tests in parallel and take the average value.

3.5.3 Blank test

Weigh the metal zirconium (3.2.4) equivalent to the sample, and do a blank test with the sample.

3.5.4 Preparation of test solution

3.5.4.1 Place the sample (3.5.1) in a.200mL polytetrafluoroethylene beaker, add 10mL hydrochloric acid (3.2.2), add 2mL hydrofluoric acid (3.2.3), heat at low temperature until the sample is completely dissolved, add 0.5mL nitric acid (3.2.1) to oxidize, and cool to room temperature.

3.5.4.2 Transfer to a 100mL plastic volumetric flask, dilute to the mark with water, and mix.

3.5.5 Preparation of working curve solution

Weigh 0.500g of metallic zirconium (3.2.4) into a set of 200mL PTFE beakers, dissolve them according to 3.5.4, and divide them after cooling.

Don't move into a group of 100mL plastic volumetric flasks, add 0mL, 0.50mL, 1.00mL, 5.00mL, 10.00mL, 20.00mL respectively Nickel standard solution (3.2.6), dilute to the mark with water, and mix.

3.5.6 Determination

3.5.6.1 Recommended analysis line wavelength. 231.60nm.

3.5.6.2 On the inductively coupled plasma atomic emission spectrometer, measure the working curve solution (3.5.5) at the selected analysis wavelength, and then When the curve linearity k>=0.999, the test solution (3.5.4) is measured, the background of the element spectrum line is checked and corrected at the appropriate position, and the The computer automatically gives the mass concentration of nickel.

3.6 Test data processing

The nickel content is calculated as the mass fraction wNi of nickel and calculated according to formula (2). The calculation result retains two significant digits.

3.7 Precision

3.7.1 Repeatability

The measured values of two independent test results obtained under repeatability conditions are within the average range given in Table 4, and the test results are absolutely poor.

The value does not exceed the repeatability limit (r), and it does not exceed 5% if it exceeds the repeatability limit (r). Repeatability limit (r) uses linear interpolation according to the data in Table 4 Method or extension method.

3.7.2 Reproducibility

The measured values of two independent test results obtained under reproducibility conditions are within the range of the average value given in Table 5, and the test results are absolutely poor.

The value does not exceed the reproducibility limit (R) and does not exceed 5% when the reproducibility limit (R) is exceeded. The reproducibility limit (R) is linear within the data in Table 5. Obtained by interpolation or extension method.